What does it mean if a question is "closed" or "on hold"?

Why are some questions marked "on hold"?

Questions that need additional work or that are not a good fit for this site may be put on hold by experienced community members. While questions are on hold, they cannot be answered, but can be edited to make them eligible for reopening.

Questions that are edited within five days of being put on hold are automatically added to a reopening queue for community review. Questions that are not reopened within five days will change from [on hold] to [closed].

Each closed or on-hold question provides a reason that helps the original poster (or other community members) know what they'd need to do in order to get the question reopened.

These are the categories of questions that may be closed by the community:

duplicate - the fundamental goal of closing duplicate questions is to help people find the right answer by getting all of those answers in one place

This question has been asked before and already has an answer. If those answers do not fully address your question, please edit this question to explain how it is different or ask a new question.

off topic - each community decides which specific topics are and are not allowed on their site.

This question does not appear to be about software development within the scope defined by the community. What's on- and off-topic is not always intuitive, so it may be necessary to reword the question to fit this site's scope after reviewing the community guidelines.

Consider editing the question or leaving comments for improvement if you believe the question can be reworded to fit within the scope.

unclear what you're asking - sometimes we need more information in order to help solve your problem

Please clarify your specific problem or provide additional details to highlight exactly what you need. The way the question is currenty written, it's hard to tell exactly what you're asking.

Edit your post to be more specific about what you're looking for, and be sure to address any concerns that other users brought up in the comments.

too broad - if your question could be answered by an entire book, or has many valid answers, it's probably too broad for our format

There are either too many possible answers, or good answers would be too long for this format. Please add details to narrow down the answer set or to isolate an issue that can be answered in a few paragraphs.

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than on facts, references, or specific expertise.

Who can put questions "on hold"?

Users with 3000 reputation can cast up to 24 close votes per day. When a question reaches 5 close votes, it is marked [on hold], and will no longer accept answers. Those users may vote to reopen questions the same way. Each user may only vote to close and reopen a given question once. (For example, if you vote to close a question that is closed and then later reopened, you cannot vote to close it again.)

Why are some questions marked "closed"?

Questions are marked [on hold] for the first five days after closure to encourage edits and improvements to the question. If a question is edited by the original poster when it is marked [on hold], it will automatically be placed in a review queue to be considered for reopening. If it is not reopened within five days, the [on hold] notice automatically changes to [closed].There is functionally no difference between an [on hold] question and a [closed] one; neither can be answered until it is re-opened, but they both allow comments, votes and edits.